Control of Congress won't be the only big question in this fall's elections. A quieter but critical battle is being waged over state-level races for secretary of state. In most states, that's the official in charge of running elections. Elections have become a political lightning rod. Many conservatives rail against voter fraud and lax rules, liberals say that's voter suppression. And now, as NPR's Peter Overby reports, superPACs want to nationalize the fight over secretary of state.

PETER OVERBY, BYLINE: The secretaries of state have their own national association. It was founded 110 years ago and meets in D.C. every winter. It's the oldest of all nonpartisan groups of elected officials, and it tries to stay that way - nonpartisan.

JOHN MCDONOUGH: We all have enough vehicles to be partisan. We keep this as a nonpartisan vehicle.

OVERBY: This is John McDonough, secretary of state of Maryland and head of the association's Democratic caucus. McDonough himself is appointed, not elected. But nationally, 31 of his colleagues run for election and are also chief elections officials in their states. Both political parties now see secretaries of state as partisan players in close elections, which means secretary of state candidates want more campaign money and more outside help. Brian Kemp, Georgia's secretary of state, is head of the Republican Secretaries of State Committee.

BRIAN KEMP: We've known for a long time how important these offices are and, you know, certainly don't have a problem with the PACs that are out there and the different groups.

OVERBY: This year, the hot, new thing is superPACs. Under the law, superPACs have no limits on their fundraising. What they cannot do is coordinate with the candidates they're supporting. The names of the superPACs are almost interchangeable. The title secretary of state abbreviates to SOS. So on the left, the SOS for Democracy superPAC. And on the right, the SOS for SOS superPAC.

Steve Rosenthal, a longtime labor and progressive strategist, is one organizer of SOS for Democracy. He says they plan to get into five or six key races and he predicts they'll be up against the best-funded of conservative activists.

STEVE ROSENTHAL: People like the Koch Brothers and Karl Rove and those who are bent on moving America in a hard-right direction.

OVERBY: Which he says means just one thing.

ROSENTHAL: We think that it's really important that progressive donors step up to the plate and do the same.

OVERBY: On the other side, Gregg Phillips is head of SOS for SOS superPAC. He's a veteran of an earlier superPAC. In 2012, Winning Our Future got millions of dollars from casino magnate Sheldon Adelson, and it kept Newt Gingrich's faltering presidential bid alive for weeks as his campaign coffers ran dry. Now, Phillips says SOS for SOS will help conservative candidates.

GREGG PHILLIPS: By nationalizing some of this and by maybe providing access to sums of money that they might not normally see come into their race.

OVERBY: He says the superPAC aims to raise between 5 million and $10 million, enough to target eight or nine races.

PHILLIPS: But also take on the other side when they stray from supporting the law or stray from supporting Americans or foster an environment where those not eligible to vote get to vote.

OVERBY: And the great thing about the secretary of state races? They've almost always been low-budget affairs. That means the superPACs might score big while spending relatively little. Peter Overby, NPR News, Washington. Transcript provided by NPR, Copyright NPR.